Conn's Flashcards
What is Conn’s?
Adrenocortical disorder characterised by excessive secretion of mineralocorticoids (mainly aldosterone) leading to systemic arteria hypertension +/- hyperkalaemia
/What do people sometimes mistake conn’s for
Renal disease - azotaemia, hypertension, low K
When is renin secreted?
Low renal perfusion, low Na
What does angiotensin II do?
Vasoconstriction
Na reabsorption
Aldosterone
Outline aldosterone as a hormone
Produced by zona glomerulosa of the adrenal cortex
Released d/t stimulation from angiotensin II
Also released in direct response to high K
/What is primary hyperaldosteronism
Conns
D/t adrenal disease (hyperplasia or tumour)
Causes release of excessive aldosterone
What is secondary hyperaldosteronism?
More common
High aldosterone due to RAAS stimulation (e.g. dehydration, low Na, low BP)
Can get clinical manifestations of secondary hyperaldosteronism (rare) –> from renal disease or a renin secreting tumour
What is the normal signalment of a Conns patient?
Middle aged to older
f=m
No breed predilection
2/3 are due to adrenal secreting tumour - carcinoma or adenoma, but can be hyperplasia
What are the 2 typical presentations of conns?
Either
hypo K induced polymyopathy
or retinal detachment + blindness/ other high BP signs
What is the additional condition patients with conns can present with?
Concurrent hyperprogesteronism
PUPD/ PP
secondary diabetes
Poor coat, seborrhoea, fragile skin, pot belly
What are you likely to see on bloods with conns?
Low K - esp in the face of adequate supplementation
Rarely see high Na
High CK
Progression of renal disease
How do you dx Conns?
Main test = plasma aldosterone assay - should be high with an adrenal tumour
Magnitude can vary between cats
Need to assess in conjunction with c/s - e.g. if only just raised but K is low then that is inappropriate and suggestive of Conns
Can be hard to dx just with this if renal disease is present as could be primary or secondary. Therefore do Plasma Renin Activity - PRA If primary (conns) - high aldosterone with low PRA
Outline the PRA test
V expensive
Used to differentiate primary and secondary HA
Special storage and transport requirements
Limitted info on what is normal
Influenced by lots of drugs e.g. ACEi and B blockers
What should you do if c/s and bloods are suggestive of conns?
Image - u/s, CT, MRI
Bloods plus imaging = dx
What is the treatment for Conns
If possible, Sx
If not - medical - anti hypertensives, spironolactone (aldosterone inhibitor),
medical tx often becomes refractory
